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Aquaponics
Technical Report · January 2016
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Oklahoma Cooperative Extension Service
HLA-6721
Aquaponics
Jimi Underwood
Oklahoma Cooperative Extension Fact Sheets
are also available on our website at:
http://osufacts.okstate.edu
Graduate Student
Bruce Dunn
Associate Professor, Herbaceous Ornamentals
Introduction
“Aquaponics” is the combination of two separate systems,
aquaculture and hydroponics. The goal of this combined
system is to simultaneously grow plants and fish in the same
system. The main advantage of doing this is because it allows
the nutrients produced by fish waste to be used by the plants,
which in turn help filter the water making it suitable for the
fish.
There are multiple approaches to aquaponics, as the term
is broad. The focus of the Fact Sheet will be systems located
within greenhouses and primarily aimed at crop production.
Aquaculture
The first part of “Aquaponics” is “aqua” meaning water and
refers to the aquaculture (fish rearing) half of an aquaponics
system.
This Fact Sheet is to give a basic overview into aquaponics with an emphasis on plant growth and does not go
into the full system of aquaponics. If you are more interested
with the fish side of aquaponics, see the additional reading
list at the end. Whichever the interest (the aquaculture or
hydroponic portion), it is a good idea to review and have an
understanding of aquaculture, more specifically recirculating
aquaculture systems, before creating an aquaponics system.
As aquaponics is two combined agriculture techniques, only
understanding one aspect is not an option.
Hydroponics (Soilless Systems)
The second part of “Aquaponics” is “ponics” which refers
to the growing technique of hydroponics the plant half of an
aquaponics system.
A brief warning, aquaponics is not hydroponics, just
as it is not aquaculture, it is a combination of the two and
creates a mini-ecosystem. While many aspects and parts of
hydroponics are in aquaponics, it is important they be treated
as separate systems with separate problems, benefits and
methods.
Hydroponics is a method of cultivating plants in soilless
systems. In hydroponic systems, the user has full control of
the nutrients and environmental conditions of the plants, compared to traditional in-soil techniques. For more information
about hydroponics, consult Extension fact sheet: HLA-6442
Hydroponics.
Aquaponics Advantages
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Requires less water quality monitoring than hydroponics
Water-efficient
No need for soil
Media beds for plant growth double as surfaces for the
nitrogen-fixing bacteria
Nutrients come from fish, no added nutrient costs (no
fertilizers)
Limited to no pesticide use
No weeding
Flexibility in location
Year-round production (in controlled environments)
Less prone to disease than hydroponics
Aquaponics Disadvantages
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High upfront costs
Higher operational costs than soil culture
High energy requirements
Requires daily maintenance
Skill and knowledge from two separate agricultural fields
required
• Requires testing of water quality for fish and plants
• Multiple ways entire system can fail
• Limited plant selection
Aquaponics in the Greenhouse
Aquaponics is not limited to greenhouse production,
but putting an aquaponics system into a greenhouse has its
advantages.
System Design
Like hydroponics, aquaponics systems have different
designs that have with their own advantages and disadvantages. The four most common types are explained below.
Basic: Flood and Drain
This is the simplest and most straightforward of the aquaponics designs. It uses a 1:1 ratios of media bed volume to
fish tank volume and it consists of a fish tank, pump and the
grow bed. It works by directly pumping the water from the fish
Division of Agricultural Sciences and Natural Resources
•
Oklahoma State University
tank into the media bed and allowing the media bed to drain
back into the fish tank.
The benefits of this system is its simplicity, but its downside is that it is fairly inflexible when it comes to ratios, as too
much water will be drained from the fish tank if trying to fill
two media beds, and the low water levels can be stressful to
the fish.
CHIFT PIST or CHOP
(Constant Height In Fish Tank – Pump In the Sump Tank,
Constant Height One Pump)
This system is very similar to the basic with the addition
of a sump tank. As its name implies, the addition of the sump
tank allows for the fish tank’s water levels to stay at a constant
height as the pump will be in a separated sump tank.
This system works by having water from the fish tank
overflow into the growing beds, which drains into the sump
tank. The sump tank contains the pump, which will pump the
water back into the fish tank.
The benefit of this system is with the water levels staying
at a constant height in the fish tank, there is no stress to the
fish. The downside has to do with layout. A sump tank will
need to be lower than the media beds, which in turn need to
be lower than the fish tank. This might require more space
or just be more difficult to find the supplies. Another thing to
watch for is if the sump tank’s water level ever gets too low,
damage to the pump can occur.
CHOP2
CHOP2 is another way to set up the CHOP system. This
system design does not require the fish tank to be the tallest
component. The design is more or less a double loop system
that has the growing beds and the fish tank run to the sump
tank. The sump tank is then responsible for pumping the water
into the growing beds and the fish tank.
This system is flexible because it essentially treats the
fish tank as another growing bed. Where the fish tank and
the growing beds differ is the growing beds make use of an
auto siphon; whereas, the fish tank just needs a gravity feed
overflow. The benefit of this system is adding growing beds
is easy, as long as the pump is strong enough and the sump
tank large enough. A negative is that the clean water from
the growing beds is mixed with the dirty water from the fish
tank, making the system less efficient at filtration.
Hybrid
The other systems mentioned here only deal with mediabased growing beds, and not raft/DWC/NFT styles of growing
beds. The hybrid system allows for these other beds to be
implemented.
Hybrid systems are still being worked out, but in one
scenario the media beds can be used as a solids filter. All
hybrid systems need other filters and components to be used
properly and effectively. If one wants to take advantage of the
benefits of the raft beds, then a hybrid system would be the
best choice.
Components
The following are basic components needed for an aquaponics system. Not all of these components are needed for
every system design, but are important in others. It is important
to check all components for clogging periodically, as all are
susceptible to the buildup of solids.
Growing Beds
The growing beds are the areas designated to grow the
crops. There are two different basic styles commonly used in
aquaponics, media-based beds and beds that grow directly
in water. Each style comes with its own advantages and disadvantages, but they both share common components.
Selecting the material for the growing beds is an early
part of aquaponics design. When selecting the material to
use as the growing bed, the first consideration is to find nontoxic and inert materials. Since aquaponics systems have
both fish and plants, the material needs to be non-toxic for
the health of the system and for the health of the consumer.
The growing bed material should also be inert, which means
the material does not leach or put materials into the system.
This is important because leaching material it can gradually
change the chemical composition in the system. It is a good
idea to avoid unlined metals, uncoated concrete and some
recycled plastics, which all have the potential to leach.
The growing beds are perhaps the best place to start
when designing the aquaponics system. Generally, a 1:1 or
2:1 (growing bed to fish tank volume) ratio is used, depending
on set design. The growing beds should take up most of the
space in the greenhouse.
Media Beds
The media beds are the most common type of growing
bed for aquaponics systems. These growing beds contain a
soilless media in which the crops will grow. In the aquaponics
systems, they play two roles – the space for plants to grow
and to help filter out toxins in the water.
Media beds function better if they are 12 inches to 14
inches deep. This gives the plants more room to send out
roots, lessens the risk of plant roots constantly sitting in water,
and provides more area for bacteria to clean the water and
provide the nutrients to the plants.
The advantage of media beds are the flexibility of the
crops that can be grown. Media beds provide areas for roots
to grow – they act similar to pots and traditional beds – making
the watering style the limiting factor in what plants can and
cannot be used.
One disadvantage of the media beds is they can be more
difficult to work with on short growth crops, such as lettuce.
This is because the crop becomes harvestable quickly and
cleaning out the roots can be time-consuming. This is not a
problem with crops that take a longer time to harvest such
as peppers. Another disadvantage is crops such as carrots,
potatoes and radishes can be deformed, depending on the
media used. This does not mean they are not edible; just an
unappealing appearance.
Media
In aquaponics, soilless media is used. This is where it
is similar to hydroponics, but aquaponics have some other
considerations that do not make all hydroponic soilless media
techniques valid for aquaponics.
First, it is important to realize what the media does in
aquaponics. The media is in charge of multiple factors. It
provides structure, air space, temperature moderation and
filters solid waste. When selecting the media, it is important
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to select media that will function within the entire system.
Gravel and clay structure tend to work best. The media must
not alter the pH of the water. This is for the health of the fish
and the plants. The media also must not decompose with
time. This is due to the chance of the media changing the
pH while decomposing. Media containing soil, wood chips,
peat moss or similar materials do not work in an aquaponics
system. The material size also is important. The media should
be large enough that it cannot be washed down and clog the
drains and plumbing systems, but small enough to encourage
root growth. This is usually about ½ inch to ¾ inch diameter
in size.
Some other factors to consider are porosity and how it
handles. The porosity helps with keeping healthy nitrifying
bacterial levels by increased surface area, as well as holding
more air and water, while making the media lighter. Handling
refers to the coarseness of the media and is only a concern
regarding user comfort when working in the media beds. The
smoother the media, the easier it will be when harvesting or
working with the plants.
Before adding the media to the growing beds, it is important to test and wash it. Testing will ensure it is inert and
pH neutral (some gravels contain limestone and other rocks
and minerals which should not be used).
Table 1 shows some commonly used media for aquaponics and their characteristics.
Raft/Deep-Water Culture (DWC)/Nutrient Film
Technique (NFT)
Raft beds are a hydroponic technique that saves time
and effort when growing certain crops. Seedlings are generally grown in rock wool or other soilless media until about a
month old, then placed on a raft that allows the roots to freely
float in the water, have water constantly flowing through the
roots or be sprayed by mist. The water used is highly oxygenated and contains the desired nutrients. Not all plants used
in hydroponics or aquaponics can use this type of bed, but it
does have its advantages.
The advantages of the raft beds are that quickly growing
crops, such as lettuce, are easier to harvest, as they simply
need to be pulled off the raft and roots can be trimmed off.
Compare this to the media beds, where once the plant is
pulled it needs the soilless media cleaned off the roots, so
the media can be re-used.
Due to the nature of the raft beds, they can be modified
to work in aquaponics. This can be done by having the water
used flow through a media bed before going back to a sump
tank or fish tank. This allows the water to go through the necessary filtration.
While raft beds can be used and many kits have them as
an option, they do have a more limited range of crops capable
of being grown using this technique.
Biofilters
Biofilters are used to clean out solid waste and toxic
chemicals such as ammonia. In aquaponics, this is done
through the media beds with the help of bacteria. More filters
and water-holding tanks can be added to the system, but this
is generally not necessary.
Rearing Tanks (Fish Tanks)
The rearing tanks depend a lot on the growing beds and
have similar considerations. They are the location of the fish
and the provider of the nutrient-rich water for the plants.
When selecting a rearing tank, it should be a similar process as for the growing beds. This is because inert, non-toxic,
food-safe materials should be used.The size of the tank should
be determined by the size of the growing beds. If using the
1:1 or 2:1 ratio in the system design, provide enough water
to be drained from the rearing tank and put into the growing
tanks without limiting the water available to the fish.
The design and placement of the tank should take into
account the weight of the filled tank. Once a tank if filled, it
is most likely going to remain in that location (water weighs
about 8.3 pounds per gallon). Choose a location that limits
the potential of people or things from falling into the tank. Try
to find a shaded location or cover the fish tank. This will help
prevent or limit algae growth in the tank.
The shape of the tank should be considered, depending
on the overall size and stocking densities. For example, in large
high-stocking density designs, it is better to use a round or oval
design because it allows water to easily flow around, limiting
dead zones of oxygen that are found in corners of square and
rectangular tanks. If only a small tank is needed, square and
rectangular designs are more space efficient and should be
considered. In both cases, tanks with more exposed surface
area to air helps with gas exchange and will help in keeping
the tank well oxygenated.
Sump Tanks
The sump tank is a water-holding tank for CHOP/CHOP 2
and Hybrid designs.The holding tank it is the lowest component
Table 1. Media.
Expanded Shale
Expanded Clay
River Stone
Weight
Crushed Stone
¾ the weight
½ the weight
Heavy
Heavy
of stone
of stone
Source
Quarry
Quarry
Rivers
Quarry
Origin
U.S.
China/Germany
Local
Local
Inert
Yes
Yes
May have
May have
Limestone
Limestone
Easy to Handle
Yes
Yes
Yes
No
Expense
Middle-range
Expensive
Cheap
Cheapest
Adapted from Rob Torcellini, Bigelow Brook Farm, LLC
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Synthetic
Light – tends
to float
Petroleum
China
Yes
Yes
Most expensive
in the system. It is needed when the system is not directly
flowing from the rearing tank to the growing beds back into
the rearing tank.
The purpose of the sump tank is to hold water, allowing
the water levels of the rearing tank to remain unaffected. Its
main purpose is to store and hold water, but it may provide
areas for temporary fish storage, depending on the water’s
oxygen and fish species.
Sump tanks are typically small and stored on the ground.
They usually can be placed underneath the growing beds,
saving space. Remember, if a pump is located in the sump
tank, it is important that the water levels are never allowed to
get low enough to cause a problem for the pump.
Plumbing
Plumbing is very important in aquaponics as they are the
connections between the other components. First, the material
used needs to be approved for use with fish and plants. You
do not want any plastics or metal plumbing that can be toxic.
Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride
(CPVC) both are common and safe to use. An alternative for
pipes is high-density polyethylene pipe (HDPE), but it has less
options in fittings and is harder to find.
When setting up the plumbing system, be sure to prevent leaks from areas where the plumbing meets the next
component. This can be accomplished using things such
as, marine-grade silicon, Uniseals® or bulkhead fittings. The
cheapest would be the silicon, but it is also the least effective
and needs to be periodically reapplied. The other two are very
effective but will have higher costs.
Mechanical and Electronic Timers
When using a flood and drain design system, a timer of
some type is needed to control the system. Mechanical and
electronic timers use a set interval to trigger flooding and
draining systems to turn on.
The mechanical and electronic timers are usually set to
work in one-hour intervals split between on and off. In most
cases the system should spend 15 minutes in the “on” position (filling the media bed) and the other 45 in the “off” position (draining). These are just typical numbers and by using
mechanical and electronic timers, adjustments can be made
until the most effective intervals are being used. If this type
of control is not desired there is the autosiphon that works
automatically and not in set intervals.
Autosiphon (Bell Siphon)
The autosiphon is an automatic, always on, method to
control the flood and drain system in the media beds. It works
by having an overflow spout. Once the water level starts filling
the overflow, it creates a low-pressure area within the siphon,
triggering the siphon to open. This quickly drains the water
from the media beds until the bed is drained and air fills the
siphon again. The siphon closes and the bed slowly begins
to fill with water again.
A similar system that uses a flood tank and a flood siphon
can also be used. It works similarly, but instead of filling the
media bed it fills a flood tank that once filled, flows into the
media bed. (This system works in a similar way to how a toilet
works.)
Autosiphons are a good choice for media beds and those
not wanting to work with timers. They are not difficult to con-
struct and operate. They do, however, need to be checked
regularly with the rest of the system.
Pumps
Pumps are needed to keep the system circulating. Most
pumps used in aquaponics are usually submersible pond
pumps, but other types are available. It is very important the
pumps do not leak anything into the water, therefore, it is a
good idea not to cut costs when selecting pumps.
Things to consider when selecting the pump are its power
in regards to flow rate and head pressure. It is generally recommended to select a flow-rate that can cycle the entire system
in about an hour and also make sure the head pressure is
high enough to pump water to the height needed. To fill two
10-gallon beds once an hour, a pump capable of moving 20
gallons of water in one hour is needed just for the beds. In
aquaponics, take the number of beds times the size of the
beds and add it to the size of the fish tank times two (to cycle
the fish water twice every hour) to get the gallons per hour
needed. For example, for two 10-gallon beds and a 20-gallon
fish tank, (2 x 10) + (20 x 2) = 60 gallon per hour needed.
The head pressure refers to height the water needs to
be pumped to, or the highest point in the system to the top
of the water surface. If the tallest bed is 5 feet off the ground,
and the top of the water surface is at 1 foot off the ground,
then the head height is 4 feet.
A pump chart can be used to determine if the pump
meets the required gallons per hour and head pressure/height
requirements. Remember the pump is a very important aspect
of the aquaponics systems and it is recommended not to cut
costs in this area.
Aeration Devices
A good aquaponics design should provide adequate
oxygen for the fish and plants. One design of an aeration
device uses diverted water coming directly off the growing
beds and flowing back into the rearing tank through a drip
system. This works by allowing the surface of the water to
absorb some air and then falling back into the main body of
water. The combination of flowing water and a drip system
should provide adequate oxygen, but other devices to provide
supplemental oxygen are recommended.
The aeration pipes and similar systems can be used to
supplement oxygen in the rearing tank. Other aeration devices are small pumps that can be placed within the rearing
tank itself. These are just common fish aeration devices that
send little bubbles throughout the tank. Consider putting an
aeration system on a separate or back-up power supply, to
ensure the fish have adequate oxygen even in the case of a
power failure.
Other considerations
Other components to consider would be things such as
indexing or sequencing valves and backup pumps.
The indexing or sequencing valves can be used to give
more control of water flow and levels if the ratio of the systems
is greater than 1:1. The indexing valve interrupts the flow of
water and the sequencing valve redirects water after every
stoppage of water flow into a new pipe. These systems help
keep water levels safe for the fish.
The backup pumps are exactly what they sound like.These
are pumps only activated if another pump fails. Although not
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required, it is a good idea to have backup pumps ready in
case a problem arises.
Water
Water is the backbone of the entire aquaponics system.
It provides the media for the fish to live in, is a necessity for
plant growth and is the method in which nutrients are spread
throughout the system.
Water source is important when establishing the system.
For example, if using city water, first the pH needs to be
checked and the method of cleaning the water needs to be
known.
Many municipalities use chlorinated water. To remove
the chlorine, run the system for a couple of days; most of the
chlorine will off-gas and be removed from the system. Once
the system is run to remove the chlorine, remember to check
the water’s pH once more, as it may have changed. Although it
is important to remove chlorine at the start of the aquaponics
system, if some water is needed just to top-off the system,
chlorinated water will be fine. When topping-off the system,
the chlorine will be at such a low rate it will have relatively little,
if any effects. If desired, a chlorine filter can be purchased to
filter the tap water prior to be using in the system.
If the water being used contains chloramine, a different
approach is necessary. Chloramine does not off-gas like
chlorine and requires an activated carbon filter or a UV filter
to break it down. This water should be filtered before filling
the fish tank or find an alternative source for water.
Water pH is important no matter what the source. The
fish in the system will prefer a neutral pH, so it important to
monitor the water pH and help maintain it at a near-neutral
level. The reason to base the pH needs off the fish is because
they are the most sensitive to the pH level. For optimal levels,
fish like a pH from 6.5 to 8.0, bacteria from 6.0 to 8.0 and
plants 5.0 to 7.0. This means a pH in the range of 6.8 to 7.0
is a good optimal target.
Action to adjust the pH should be taken when it drops
below 6.4. To adjust the pH levels, slowly add calcium hydroxide (hydrated lime) or calcium carbonate (agricultural
lime) alternatively with potassium carbonate, bicarbonate
or potassium hydroxide. Slowly add and check the pH every
few hours adding more if necessary. It is important to do this
process slowly to avoid a pH spike from adding too much too
quickly.
Action to adjust the pH should be taken when it rises
above 7.4. When adjustment is needed, check with your local
hydroponic or aquaponics store for some nitric or phosphoric
acid-based products. Again, it is important to add the product
slowly to prevent a sudden change in pH.
The last factor of water to consider is the dissolved
oxygen content. The correct level is determined by the fish
species, and in most cases, it is better to be a little high than
low. Dissolved oxygen can be monitored using a dissolved
oxygen meter and can be added into the system by aeration
devices or flowing water.
Temperature
There are two separate temperatures that are very
important to monitor in aquaponics. Both are determined by
the species of fish and plants chosen, but they differ in the
way they are controlled.
The first temperature to keep track of is the air temperature
of the greenhouse. The air temperature is determined by the
plant needs at the seasonal conditions. Air temperature can
be controlled using common greenhouse practices of heaters,
fans, shade cloth and other methods. Refer to information on
the crops being grown to determine best cultural practices to
have the greenhouse set at the right temperature.
The second temperature to keep track of is the water
temperature. This is determined by the fish species. Some
species of fish will prefer warmer or cooler environments, so
it important to know in what conditions the selected species
thrives. It may also be a good idea to select fish species from
similar climatic zones as the greenhouse. This is simply because it can be easier to keep water temperatures close to
the surrounding areas. Fish that thrive in those temperatures
should require less temperature inputs. Providing the ideal
water temperature removes a potential stress for the fish. To
control water temperature in smaller fish tanks, a traditional
aquarium heater can be used. Larger tanks will require different
methods such as swimming pool heaters or in-floor heating.
It also is important to look at ways to retain heat by insulating
the fish tank and areas where cold spots might develop. Like
many components in aquaponics, doubling up and having a
back-up is a good way to help prevent problems in the case
of one heater malfunctioning.
Avoid overheating the water in the aquaponics system. It
is easier and more affordable to heat water than it is to cool
water. Another reason to avoid excessive temperatures is
warmer water holds less dissolved oxygen.
Bacteria
Bacteria (Nitrosomonas and Nitrospira) play an important
role in aquaponics systems, as they are responsible for nitrifying ammonia (toxic to fish) into nitrate, which is safe and more
readily available to plants. These nitrifying bacteria are aerobic
autotrophs and require oxygen to survive, they need a surface
to colonize, are very efficient at their conversion of ammonia
to nitrites and they need a moist environment to survive. The
Nitrosomonas create nitrites from their consumption of ammonia. Nitrites are still toxic to fish, so Nitrospira is needed,
which consume the nitrites and create the wanted nitrates.
How to care for these bacteria is not overly complex. If the
right conditions are provided, the bacteria should be able to
thrive. The main component in keeping the bacteria alive is the
presence of ammonia. So if there is a low stock level of fish,
there will be lower levels of ammonia, leading to lower levels
of bacteria. The reverse is also true, meaning high stocking
levels can lead to higher ammonia levels, which provide more
food for the bacteria, leading to more bacteria.
Oxygen levels are also very important in keeping the
bacteria healthy. If oxygen is cut off, the bacteria will die off
slowly. If oxygen becomes low, the bacteria will reverse their
process and turn the nitrates into ammonia in a process known
as dissimilation. This is easy to identify when it occurs, due
to a clog in the grow bed, it begins to produce an ammonia
odor.
A critical thing to control is dramatic temperature changes,
which affect fish activity. If the temperature drops, the fish activity can drop, leading to less ammonia. If the temperature rises
rapidly, the fish activity and feeding rise and can overwhelm the
bacteria with ammonia. This is something to monitor if owning
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an outdoor system. In a greenhouse setting, the controlled
environment should prevent dramatic temperature swings.
The ideal temperature range for healthy and actively
reproducing bacteria is 77 F to 86 F, with activity dropping
below this range and stopping at 39 F. Death of the bacteria
will occur below 32 F and above 120 F.
Monitoring and controlling pH is also an important factor
to the bacteria’s health. For the Nitrosomonas bacteria the
optimal range is 7.8 to 8.0 and for the Nitrospira bacteria it is
between 7.3 to 7.5. Levels below 7.0 will slow the Nitrosomonas
and lead to increases in ammonia in the system. Nitrification
becomes inhibited if the pH is allowed to drop below 6.0. (Hill,
2008)
Bacteria play an important role in providing nutrients to
the plants and cleaning out ammonia for the fish. They are
essential to a functioning aquaponics system and need to be
cared for properly.
Fish for Aquaponics
Plants for Aquaponics
How nutrients are handled in aquaponics differs from
traditional soil gardening and hydroponics due to the presence
of fish.
In aquaponics, the fish tanks supply the nutrients through
the fish waste. Nitrogen is provided through the nitrifying bacteria and the other nutrients are deposited in the media. In a
functioning aquaponics system, new supplemental nutrients
do not need to be added as in other soilless systems.
Many of the nutrients may take some time before they
build up to significant levels in the system, so when beginning
an aquaponics system, it is important to choose plants that are
not high nutrients users (such as cucumbers and tomatoes).
Once the system has become established and nutrients have
been allowed to build, high nutrient plants thrive.
It is the build in nutrient supply that makes aquaponics
unique to soilless systems. This system relies on fish, bacteria
and plants to create a complete aquaponics system.
Many plants can be used in aquaponics, although choices
are limited or guided by stocking density, choice of growing
beds and other environmental factors. Due to the nature of
the system, many plants that do well in hydroponic systems
can do well in aquaponics. These include vegetables such
as tomatoes, lettuce, cucumbers and peppers, as well as
ornamentals such as herbs, roses and foliage plants. Table
2 (on page 7) shows 10 commonly used aquaponics crops
and their preferred conditions. When selecting plants, it is
important to know the nutrient requirements and how they
correspond with the fish stock levels.
Low-nutrient plants require only a low or normal stocking
density of fish. These plants include herbs, lettuce, broccoli
and more.
High-nutrient plants can also be used in aquaponics.
These require a higher stocking density to provide adequate
nutrient load for the plants.Tomatoes, peppers and cucumbers
fall into this category.
Environmental conditions also play an important role in
an aquaponics system. Although the aquaponics systems
discussed here are for greenhouses, which have controlled
environments, it is a good idea to grow plants with higher
temperature and light requirements in the summer and lower
temperature and light requirements in the winter. An example
of this would be to focus on tomato and pepper production
during the spring and summer months and lettuce and cauliflower in the winter.
There are many factors to consider when selecting the
type of fish to use. These include water temperature and tank
needs (are heaters and other supplies needed?), purpose
of having the fish (just a nutrient source for the plants or are
they a food source as well?), state laws (some states have
restrictions on certain fish) and availability.
Fish commonly used in aquaponics are tilapia, trout, catfish, bass, goldfish, koi and pacu. Each have their own preferred
temperature range, food preferences, size and oxygen needs.
Table 3 has a list of common fish for aquaponics and some
of their traits. For example, trout typically like cold water and
need high oxygen levels compared to the others mentioned.
This makes them a bit more complicated to care for, but trout
can obtain a higher selling price in the right market.
Nutrients
Fish and System Sources
Organics OKC Garden Supply
2800 N. Penn
Oklahoma City, OK 73107
http://www.organicsokc.com/
Tulsa County Hydro-Organics
1928 W. Albany
Broken Arrow, OK 74015
Table 3. Fish.
Edible
Temperature range (°F)
Optimal Temperature (°F)
Carnivore or Omnivore
Mature Size
Time to maturity
Oxygen Needs
Tilapia
Trout
Catfish
Bass
Goldfish
Koi
Pacu
Yes
60 - 90
74 - 80
O
1.5 lb.
9 – 12 mos.
Low
Yes
35 - 68
55 - 65
C
0.8 lb.
12 mos.
High
Yes
35 - 95
75 - 85
O
1.25 lb.
12 – 18 mos.
Low
Yes
40 - 90
74 - 80
C
1 – 3 lbs.
15 – 18 mos.
Low
No
35 - 90
65 - 75
O
4”
3 yrs.
Low
No
35 - 90
65 - 75
O
20 lbs.
3 yrs.
Low
Maybe
60 - 95
74 - 80
O
60 lbs.
4 yrs.
Low
Adapted from Sylvia Bernstein’s Aquaponic Gardening: A Step-by-Step Guide to Raising Vegetables and Fish Together
HLA-6721-6
HLA-6721-7
Adapted from Appendix 1 of Somerville, C., and et. Al. 2014. Small-scale aquaponic food production. Integrated fish and plant farming. FAO Fisheries and Aquaculture Technical Paper No. 589.
*Plants need to be shaded in high temperatures.
High
Normal
Normal
Media beds,
Normal
DWC, and NFT
Media beds, and High
DWC
Media beds,
DWC, and NFT
Media beds,
DWC, and NFT
Media beds
Normal
Normal
High
Media beds
Media beds
Media beds,
and DWC
Media beds
High
High
Media beds,
Basil
5.5-6.5
6”-10”
5-6 weeks
65°F - 86°F
Full*
12”-28” x 12”
Optimal: 68°F - 77°F
DWC, and NFT
Broccoli
6.0-7.0
16”-28”
60-100 days
56°F - 65°F
Full
12”-24” x 12”-24”
Cabbage
6.0-7.2
24”-32”
45-70 days
59°F - 68°F
Full
12”-24” x 12”-24”
Cucumbers
5.5-6.5
12”-24”
55-65 days
72°F - 83°F (day)
Full
8”-80” x 8”-32”
65°F - 68°F (night) Eggplant
5.5-7.0
16”-24”
90-120 days
72°F - 79°F (day)
Full
24”-48” x 24”-32”
59°F - 65°F (night)
Lettuce
6.0-7.0
7”-12”
24-32 days
59°F - 72°F
Full*
8”-12” x 10”-14”
Flowering over 76°F
Parsley
6.0-7.0
6”-12”
20-30 days
59°F - 77°F
Full*
12”-24” x 12”-16”
Peppers
5.5-6.5
12”-24”
60-95 days
72°F - 86°F (day)
Full
12”-36” x 12”-32”
58°F - 61°F (night)
Swiss Chard
6.0-7.5
12”
25-35 days
61°F - 76°F
Full*
12”-24” x 12”-16”
Tomatoes
5.5-6.5
16”-24”
50-70 days
72°F - 79°F (day)
Full
24”-72” x 24”-32”
on to 8-10 months
56°F - 61°F (night)
Stocking
Density
Aquaponics
Method
Plant Size
(Height x Width)
Crop
pH
Spacing
Growth Time
Temperature
Light
Table 2. Common Crops for Aquaponics.
Willow’s Garden Supply
11630 E. 51st St.
Tulsa, OK 74146
www.theaquaponicsource.com
www.backyardaquaponics.com
http://urbanfishfarmer.com/
Additional Reading
Aquaponic Gardening: A Step-By-Step Guide to Raising Vegetables and Fish Together by Sylvia Bernstein
http://www.aquaponic.com.au/
http://afsic.nal.usda.gov/aquaculture-and-soilless-farming/
aquaponics
NM State: Is Aquaponics Right For You?
Oklahoma based: Symbiotic Aquaponic http://www.symbioticaquaponic.com/
FAO Fisheries and Aquaculture Technical Paper No. 589
(Small-scale aquaponic food production. Integrated fish and
plant farming.)
Range, Paul, and Bonnie Range. Simplified aquaponics manual.
Backyardaquaponics.com/Travis/Simplified-Manual.pdf
Measuring for pumps: https://www.brightagrotech.com/pumpsfor-aquaponics-or-hydroponics/
Factsheets on Aquaculture from OSU and resources
from the Southern Regional Aquaculture Center (SRAC) are
listed below:
NREM-9201, Getting Started in Aquaculture
NREM-9207, Recirculating Aquaculture Systems: Questions
to Ask Before You Invest
SRAC 451, An Overview of Critical Considerations
SRAC 452, Management of Recirculating Systems
SRAC 454, Integrating Fish and Plant Culture
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